Between January 1992 and May 2004, 189 patients underwent allogeneic bone marrow transplantation (BMT) for haematological malignancies from HLA-identical sibling donors in our transplantation unit. Of the 189 patients, 2 developed eosinophilic fasciitis (EF). The first patient developed Hashimoto's thyroiditis and EF 11 and 21 months after BMT, respectively. In the second patient EF occurred 9 months after BMT, accompanied by antinuclear antibodies, antiextractable nuclear antigens and antigliadin antibodies. Both patients were treated with extracorporeal photochemotherapy (ECP), resulting in improvement of fasciitis in both and normalization of antithyroid antibodies in the first patient. Our data confirm the rarity of fasciitis after BMT and the efficacy of ECP, recently applied experimentally in one patient for the treatment of fasciitis after BMT. Moreover, we report for the first time the association of fasciitis with autoimmune phenomena after BMT. The correlation between the two entities is supported by remission of Hashimoto's thyroiditis after ECP treatment for fasciitis.